An organic light-emitting diode (OLED) is one of the hot spots in the research field of current panel display. Compared with a liquid crystal display (LCD), the OLED display has advantages of low energy consumption, low production cost, self-luminescence, wide viewing angle, and fast response speed, etc. In contrast to the LCD that uses a stable voltage to control brightness, the OLED is driven by a current and requires a steady current to control its light emitting. Generally, in the OLED display, a data signal is inputted to a gate of a drive transistor in a pixel circuit through a data line, and a power supply voltage VDD is inputted to a source of the drive transistor through a power signal line, such that the drive transistor may generate a driving current under the effect of a gate-source voltage to drive the connected OLED to emit light. Due to reasons such as processes and aging, there may be a drift in a threshold voltage Vth of the drive transistor in the pixel circuit, which may cause that the current flowing through each OLED varies under the influence of the drift in the threshold voltage Vth, and may further cause an unevenness in displaying brightness. Thus, a visual effect of an overall image may be affected.
Since the current flowing through each OLED is related to the power supply voltage VDD connected to the source of the drive transistor, the power supply voltage VDD received by the drive transistor in the pixel circuit needs to be constant in an ideal state. However, as the OLED display in color display, since different color pixel units emit light differently, the currents flowing into OLEDs in different color pixel units are different, such that the current in the power signal line also fluctuates, resulting in a fluctuation of the IR drop on the power signal line. Thus, the voltage value of a high-potential signal VDD inputted to the pixel circuit may change, resulting in the current difference in different regions and further causing the occurrence of unevenness in displaying brightness of the OLEDs in different regions. The disclosed device structures and methods are directed to solve one or more problems set forth above and other problems.